Multiple spindle machine



Dec. 10, 1940. J. B. JOHNSON ETAL MULTIPLE SPINDLE MACHINE Filed July 8, 1937 13 Sheets-Sheet l Dec. 10, 1940. J. B. JOHNSON ETAL MULTIPLE SPINDLE MACHINE Filed July 8, 1937 13 Sheets-Sheet 2 Dec. 10, 1940. J. B. JOHNSON EI'AL 2,224,265

MULTIPLE SPINDLE MACHINE Filed July 8, 1937 13 Sheets-Sheet 3 Dec. 10, 1940. J. B. JOHNSON ETAL MULTIPLE SPINDLE MACHINE Filed July 8, 1937 15 Sheets-Sheet 4 2 fat/ 547 2220 J. B. JOHNSON E'I-I'AL MULTIPLE SPINDLE MACHINE Dec. 10, 1940.

Filed July 8, 1957 1.3 Sheets-Sheet 5 Dec. 10, 1940- J. B. JOHNSON ETAL 2,224,265

MULTIPLE SPINDLE MACHINE 13 Sheets-Sheet 6 Filed July 8. 1937 Dec. 10, 1940. J. B. JOHNSON EIAL 3% MULTIPLE SBINDLE MACHINE Filed July 8, 1957 15 slams-sheet v Dec. 10, 1940. J. B. JOHNSON ETAL MULTIPLE SBINDLE MACHINE 15 Sheets-Sheet 8 Filed July 8, 1937 Jfig 2172220022 @2 27275 42%; 1 WM W Dec. 10, 1940. J. B. JOHNSON ETAL MULTIPLE SPINDLE MACHINE Filed July 8, 1937 l3 Sheets-Sheet 9 Dec. 10, 1940.

1.3 Sheets-Sheet 10 Filed July 8, 1937' J. B. JOHNSON arm. 2,224,265

MULTIPLE SPINDLE MACHINE Dec. 10, 1940. J. B. JOHNSON ETAL MULTIPLE SPINDLE MACHINE Filed July 8, 1937 15 Sheets-Sheet 12 Dec. 10, 1940. J. B. JOHNSON EI'AL 2,224,265

MULTIPLE SPINDLE MACHINE Filed July 8, 19;"! 1s Sheets-Sheet 1:5

fad/2%)" J/Zwm Patented Dec. 10, 1940 PATENT OFFICE MULTIPLE SPINDLE MACHINE Joseph B. 'Johnson and Merton H. Arms, Springfield, Vt., assignors to Bryant Chucklng Grinder Company, Springfield, Vt., a corporation of Vermont Application July 8, 1937, Serial No. 152,582

59 Claims.

This invention relates to multiple spindle machines, and more particularly to such machines where the operating tools are grinding wheels.

One of the objects of this invention is to provide for individual traverses of the several tools with respect to their respective work pieces.

A further object is to provide for independent angular adjustments of the tools, relative to the axes of their respective work pieces.

Another object is to provide means whereby the work pieces are moved to retract or present them into operative relation to the tools so that the normal extent of traverse of the tools may remain unchanged. This, coupled with a dead center control of the traverse, prevents overtravel of the tools, which is of particular importance when working to shoulders and blind holes in the work.

Still another object is to provide for automatic truing of the tools or wheels to an independently adjustable extent when the work pieces are retracted.

A further object is to feed the tools relative to the work transverse to the relative indexing motion therebetween so that slight inaccuracies of indexing have negligible effect on size of the finished work.

Another object is to provide improved means for adjusting grinding wheel truing devices to compensate for wear and wheel truing.

A further object is to provide for means for adjusting relatively adjacent parts whereby high accuracy of work may be produced without requiring more than easily attained commercial accuracy in the machining of the parts.

A further object is to provide improved constructions for protecting bearings from access of foreign matter.

Further objects and advantages will appear from a more complete description of certain embodiments of the invention disclosed in the accompanying drawings, in which Figure l is a side elevation of a grinding machine embodying this invention.

Figure 1a is similar to a portion of Figure 1, but to a larger scale.

Figures 2 and 3 are left and right end elevations, respectively, of the machine.

Figures 4 and 4a, together constitute a section on line 4-4 on Figures 3, 7 and 14.

Figure 5 is a fragmentary sectional detail to a larger scale than Figure 4.

Figure 6 is a detail section on line 6-6 of Figure 4.

Figures '7 and 8 are detail sections on the corresponilingly numbered section lines on Figures 1 and Figures 9 and 10 are cross sectional views on line 9-9 of Figure 8 showing two positions of the locking pin.

Figure 11 is a detail section on line ii-li 0! Figure 2, but to a larger scale.

Figures 12 and 13 are detail sections on correspondingly numbered section lines of Figure 11, Figure 13 being on a smaller scale.

Figures 14 and 15 are detail sections on the correspondingly numbered section lines of Figures 1 and 4.

Figures 16 and 17 are cross sectional views on line l6-l6 of Figure 15 and showing the driven l5 mechanism in released and latched positions, respectively.

Figure 18 is a fragmentary section on line Ill-l8 of Figure 4.

Figures 19, 20 and 21 are detail sectional views 20 on the correspondingly numbered section lines or! Figure 18 and Figure 21 is also a sectional view, on line 2l-2l of Figure 20.

Figure 22 is a detail section on line 22-22 of Figure 4. 25

Figure 23 is a detail section on line 23-23 of Figures 3 and 24.

Figure 23a is a detail section to a larger scale on line 2311-2311 of Figure 23.

Figure 24 is a sectional view on line 24-24 of Figures 4 and 23.

Figure 25 is a partial section on line 25-2501 Figure 1. v

Figure 26 is a front elevation of the mechanism i shown in Figure 25. 5

Figures 27 and 28 are partial crosssectionalviews on lines 21-21 and 28-28, respectively, of Figure 1.

Figures 29 and 29a are views to a larger'scale" 35-35 of Figure 1, showing'the'valve in different so 1 positions.

Figure 37 is a detail section on line Figures 1 and 4. Figure 38 is a detail section to on line 38-38 of Figure 1.

a larger scale Figure 39 is a view similar to a portion of Figure 4, but showing a modification.

Figure 40 is a detail section on line 40--40 of Figure 3 and Figure 42.

Figure 41 is a portion of Figure 40 to a larger scale.

Figure 42 is a sectional view on line 42-42 of Figure 40.

Figures 43 and 44 are detail sections to a larger scale on lines 4343 and 44-44 of Figure 42.

Figure 45 is a detail section on line 4545 of Figure 40 to a larger scale.

Figure 46 is a top plan of a portion of the machine shown in Figure 40.

Figure 4'7 is a diagram of the hydraulic system.

In the machine illustrated both the tools and the work are mounted for reciprocation in line with each other, the tools being reciprocated to :0 effect traverse of the tools relative to the work,

and the work being reciprocated to and from operative relation to the tools to begin the tooling operation and to withdraw the work from the tools after the tooling operation has been com- 1'5 pleted. When the tools are grinding wheels, these wheels may be trued while the work is out of grinding position, the truing devices being brought into operative positions for the truing operation. After truing has been effected, the

truing tools are automatically retracted.

Work holders and mountings therefor Referring first to Figures 1 and 4, at I is shown a machine base having a pair of standards 2 and 3 adjacent to opposite ends, these standards being provided with bearing sleeves 4 and 5, respectively. Mounted for rotary and recipro catory motions in the bearings 4 and 5 is a shaft 8 which not only supports the work holders, but

also, as will later more particularly appear, supports a guide for the tool holders. Secured to a portion of the shaft 6 between the bearings 4 and 5 is a hub portion 1 of a work holder-carrying spider I. As shown best in Figure 8, this spider 5 comprises a housing portion 9 adjacent to one end of which are positioned a series of platforms ll, four being shown, to which are secured with capability of angular adjustment, work-holding heads II. A pivotal connection for each of these 50 work-holding heads comprises a stud l2 journaled in a portion of the housing 9, each of these studs having an eccentric pivot extension [4 Journaled in the casing of the head ll. tric pivot mounting provides an accurate adlusting means for the pivotal center of each of the work-holding heads, the axis of which, as shown, may lie between end faces'of the work.

A most important reason for this eccentric mounting is that it permits the axes of the heads to be brought the same distance from the axis of the shaft 4, and is valuable even when grinding straight holes, as the radial distance from this axis to the axes of the heads has a direct bearing on the size of the holes ground. The 55 adjacent face of the head II is shown in Figure 4 as provided with 'a series of bearing ribs II which ride on the adjacent face of their respective platform II, and the head H is adjustably secured in the desired angular relationship to the 1 axis of the shaft 6 as bymeans best shown in Figures 4 and 37. Each of the heads H is provided with a bearing 16 for a post "which is provided between the head I I and the platform II with a head It. This head is threaded latorally of its axis for engagement with a threaded This eccenadjusting rod i3 which is Journaled in a plug 20 rockably mounted in a bearing 2| adjacent to the outer edge of each platform III. A pair of collars 22 arranged on each side of a flattened end of the plug 20 hold the rod l9 against axial 5 motion and its outer end is shown as squared off at 23 for the reception of a tool by which it may be turned. A cap piece 24 secured over the outer face of the rod l9 holds it in position and a washer 25 held on by a cap screw 26 holds the 10 plug 20 against removal from its bearing II. This mounting provides means for so adjusting each of the work heads as to determine whether or not straight or tapered grinding is to be effected. If the head is adjusted so that the axis 16 of the work is parallel to that of the shaft 4, the work will be ground straight, while any variation from parallelism with the axis 6 will result in taper grinding, the amount by which the axis of the head is out of parallelism determining the :0 angle of the taper.

Journaled within the casing of each head II is a work spindle 30, which carries within the casing a work holding member II which may be of any suitable description. As shown this work 28 holder 3| is provided with spiral ribs 32 on its outer face bearing on the inner face of the casing so arranged that as the work holder is rotated, these spiral ribs tend to force out from between the casing and the work holder any foreign matso ter which might otherwise find its way therebetween.

The type of work holder herein shown is intended for gripping the outer face of internal work to be ground, and in Figure 40 it is shown 36 as comprising a plurality of fingers 35 which can be brought toward each other to clamp the work in position by a wedging engagement of their outer ends with an outer shell 38. These fingers 35 are moved axially into or out of work-grip- 4o ping position, being carried by a hollow plunger 31 which extends axially through the spindle 3|, and as shown best in Figure 38, secured to a head 38. This hollow plunger 31 has suitably secured thereto at its rear end, a sleeve 39 having slots 39a in which ride spokes 38a from the head a and against the forward end of which bears a heavy coil spring 40 which normally holds the plunger 31 in work-holding position. Back of the head 38 is positioned a piston 4! which carries on its face adjacent to the head 38 a brake ring 42. This piston is mounted in a cylinder 43 secured to the outer end of the casing for the work head II and at suitable times fluid under pressure may be admitted back of the piston 4i to force it forwardly against the rear face of the head 38 and thus apply a braking force to the rotation of this plunger 31, and forcing the plunger 31 axially in a direction to release the work. The plunger 31 when in its work-holding go position is effectively keyed for rotation with the spindle 30 by its wedging engagement with the forward end of the spindle and the braking effort exerted against the head 33 is therefore effective to stop the rotation of the spindle before the work is released. Rotation of the work spindle itself is produced by rotation of a belt pulley 45 keyed thereto by the key 46. The spindle .is mounted in suitable spaced bearings 41 and as within the work head casing. The pulleys 4' on the respective work spindles are each driven individually as by a belt 50 (see Figure 2) passing thereover from an individual drive pulley ll. Each drive pulley ii is connected as through a flexible shaft 52 to a main drive pulley u and a belt 54 passes about a plurality of drive pulleys 53 and a pulley 55 of a driving motor 56. It

will be noted by reference to Figures 2 and '7 that one of the pulleys 53 is out of engagement with 5 the drive belt 54, so that in this angular posip tion the work spindle is not being rotated, this being at the loading and unloading station in the indexing of the various work holders and of the spider 8, which is accomplished by means hereafter described. The motor 56 is shown as pivotally mounted at 66 to a bracket 6| secured to the side of the machine bed I. Tension on the belt 54 is produced by a tension spring 62 secured to a lug 63 projecting from the motor support 64 and a safety bar 65 carried by the bracket 6| and passed through a hole 66 in the motor base 64 prevents the motor from swinging violen-tly outwardly should the belt 54 break.

The entire work holding spider is moved axially to bring the work holders simultaneously into or out of operative relation to the grinding wheels by reciprocation of the shaft 6 and for this purpose hydraulic mechanism is herein shown. The

shaft 6 at its right hand end, as viewed in Figure 4, is connected to a pistonrod I6 secured to a piston H (see Figure 4a) riding in a hydraulic cylinder I2.

Means are provided for introducing coolant to the work and fluid under pressure to operate the 80 chuck through the shaft 6. For this purpose the left hand end of the shaft 6 is hollow and positioned therein is a fluid pressure distributing mechanism comprising an inner coolant pipe I5 and four fluid pressure pipes I6 arranged in circular array therearound. Four such pipes are shown for the reason that there are four spindles,

but if any other number of spindles should be desired, the number of fluid pressure pipes would be made to correspond. The central pipe I5 extends through a packing gland 'I'I within which it may be rotated and which couples it with the end of a stationary coolant supply pipe 18. The

inner end of the pipe 15 enters into a distributing head I9 from which extend short pipes 86 which are connected as through flexible pipes 8| with central pipes 82 passing axially through the plungers 31 and opening between the work-holding jaws of the several work spindles. The pipes I6 communicate at their outer ends with a head 85 rotatably mounted in a stationary distributing collar 86 which is provided with a pressure supply pipe 81 and a port which communicates with that pipe 16 which leads to the work head in the loading and unloading station only. Each of these pipes I6 communicates through its individual outlet pipe 88 and a flexible pipe 89 with its pressure cylinder 43 back of the piston 4|. This fluid pressure is opposed by a coil spring 96, as shown best in Figures 4 and 38. In Figure 39 a modification is shown in which instead of employing a common motor, such as 56, for driving the various-work holders except at the loading and unloading station, an individual motor is employed for each work holder. Such a motor is shown at 9| and is provided with a belt pulley 92 on its armature over which extends a belt to the driving pulley 45 of the individual work spindle, shown generally in this flg- 70 ure of a type similar to that illustrated in Figure 4.. v p

Indexing mechanism The indexing is produced by step by step rotation of the shaft 6, together with the spider 8' duced when the shaft 6 with the parts carried thereby is retracted from operative relation to the grinding wheels. For producing this indexing motion the left hand end portion of the shaft 6 has keyed thereto a Geneva wheel I66. This Geneva wheel I66 besides acting as a portion of the indexing mechanism, is provided also with cam mechanisms which control the wheel traverse and the wheel truing, as will later be described more specifically under these respective 1o headings. As shown best in Figure 2, this Geneva wheel I66 is provided with slotsgIOI, one for each of the work spindles, with which cooperates an indexing arm I62 having a roller I63 joumaled at its outer end for engagement in the slots MI. 15 This arm I62 is Journaled on a stub shaft I64 and has secured to or integral therewith a gear segment I65 with which meshes a rack bar I66 forming the piston' rod of a hydraulic cylinder I61. On reciproca ion of this rack bar I66 from 20 the full to the dott d line position shown in Figure 2, the arm I62 swung through an arc sufficient to move? the Geneva wheel I66 through the desired angular distance necessary to index the turret from one to the succeeding angular posi- 5 tion to change the work holders from one to a succeeding station.' It will be seen that the Geneva wheel I66 is out of axial position to be ,engaged by the arm I62 when the work spindles are in their relative operative positions, the work 30 spindles then being in the full line position shown in Figure 4, the indexing occurring when the shaft 6 has been moved axially into the dotted line position shown in Figure 4. When the arm I62 has reached its dotted line position shown in 5 Figure 2 to complete the indexing motion, it strikes upon a lever I 68 (see Figure 2), and the depression of this lever actuates a flexible release cable I69, the inner end of which is operatively related to a valve mechanism which admits fluid 40 under pressure to the left hand side of the piston II, shown in Figure 4a, and returns the shaft 6 axially to the normal operative position of the work holders. Details of this valve mechanism will be taken up under a discussion of the hy- 45 draulic system.

Means provided for locking the spider 8 in any of its indexed positions with extreme accuracyis shown best in Figures 8, 9 and '10. It will be noted that the spider 8 is provided with four lock- 50 ing and guide projections II5, provided on each side with hardened wear plates H6. The machine base I provided with a cross frame portion I H which is provided with a ciit-out portion II8 between which one of the projections H5 is 55 positioned in any indexed angular position of the spider and when the spider is axially in operative position. When the spider is retracted for indexing, these projections I I5 are drawn laterally out of the plane of the cross frame member I", 60 so that the spider is free to be indexed. vOne side of the cut out portion II8 has positioned therein a locating face member II9 which is formed as the outer face of a headed pin I26, andone of the wear pieces N6 of each of the extensions H5 85 when brought up firmly against this surface insures the correct angular position of the spider 8 after each indexed position. Opposite to this surface member H6 is positioned an abutment rod I25 having a head I26 which may engage 70 with the opposite wear piece H6 and push upon this wear piece to press the other one against the locating surface member H6. This abutment rod I25 is slidably mounted in the frame portion III and has fixed to its outer end a piston I36 78 against the outer face of which fluid under pressure may be admitted, as through a port I3I in a cap I32, which closes off the outer end of the cyl- ,inder I33 within which the piston member I80 is slidable. The direction of drive of the belt 56 by which the work spindles are rotated is such as to tend to hold the extensions II5 against the inner face of the abutment rod I25 and away from close contact with the locating abutment face member II9, but when the spider has fully entered between these two abutment members, fluid under pressure being admitted behind the piston I30, forces one of the extensions II5 into close contact with the locating face. This construction insures minimum wear on the locating face II9, since during the axial motion of the spider this spider bears against the movable abutment rod I25 and is only brought up against the accurate locating face II9 when its axial motion has stopped. The wear of rubbing contact is thus entirely on the opposite wear plate I I6 and on the movable abutment member I25. The indexing position of these parts is shown in Figure 10, while the locked position is shown in Figure 9.

Grinding wheel mounting and-traversing mechanism The standard 8 at the right hand end of the machine, as viewed in Figure 4, is extended above" the bearing 5 to form a housing indicated generally at I50, and within this housing and arranged about the axis of the shaft 6, are a plurality of grinding wheel carrying units, there being one less unit than there are work spindles so that there is no unit at the loading and unloading station of the work holders. Since as herein illustrated, there are four rotary work supports, there are three grinding wheels. Each of these units, as shown best in Figure 23, comprises a pair of alined tubular portions I55 and I56 connected intermediately by an enlarged casing portion I51. The tubular portions I55 and I56 are journaled in tapered bushings I58 and I59 carried in bearing sleeves I60 and I6I secured in opposed relation in opposite walls of the casing member I50, so that the axes of the sleeve portions I55 and I56 are arranged parallel to the axis of the shaft 6. These sleeve portions I55 and I56 are mounted for axial as well as rocking motion in their respective bushings and in order to take up wear, the bushings are shown as split, the split ends having their opposed faces tapered, as shown at I in Figure 23a, for cooperation with mating tapered faces of an adjusting piece I66. This piece 166 has threaded engagement with adjusting screws I61 and I68 mounted in the bearing sleeves I60 and I6I so that the adjusting pieces I66 can be forced outwardly, extending the bushing to permit the desired rocking and axial motion of the sleeve I55 and I56, and the bushings are also capable of axial adjustment as by the adjusting screws I68a.

In each of the sleeves I56 is journaled a grinding wheel drive shaft I10 carrying on its outer end beyond the sleeve I56 a driving pulley I" which may be belted to pulleys I12 on an armature shaft I18 of a driving motor I14. The varia spring idler pulley I11 by which it may be held ,under proper tension and about a pulley I18 on end of this shaft I19 is secured the grinding wheel' I which constitutes the operative tool of the machine. This shaft I18 is carried in suitable bearings (not shown) in a unit shaft housing "I which may be of standard construction.

The several grinding wheels are arranged to be traversed independently of each other. To this end, each of the sleeves I56 has fixed thereon, as by a nut I85, a circular rack I86 and engaging the teeth of this rack are teeth on a sector I81 secured to a rock shaft I88 (see Figures 23 and 24). This rock shaft I88 is Journaled within a bracket I89 and on the opposite side of this bracket from the segment I81 it carries a crank arm I90. To a crank pin I9I at the free end of this crank arm is pivoted one end of a link I92. The opposite end of this link carries a second stud I93 having a squared head I riding in a slot I95 of an arm I96 secured to a rock shaft I91. This rock shaft is journaled in a portion of the same bracket I89 and has pinion teeth I98 'cut therein with which mesh the teeth of a rack bar- I99. This rack bar I99 forms an intermediate portion of a double acting piston mounted in a fluid pressure cylinder 200. By admitting fluid under pressure toopposite sides of this piston, the rack bar is driven in one or the other direction as to turn the sector I81 and reciprocate the tool head in its hearings on the sleeves I55 and I58. It will be noted that the grinding wheels I80 are eccentrically disposed to the rocking centers of their respective carrying units and hence it is necessary to accurately determine the angularrelation of the wheel units in order to insure the proper position of the grinding wheel with relation to.

the work and change of this relation is also availed of to accomplish thefeeding motion of the wheel with relation to the work. This an.- gular position of each of the wheel units, as shown, is controlled by the engagement of an adjustable portion thereof on a controlling contour or abutment member. As shown this contour or abutment member comprises a sleeve 2I0 which surrounds the shaft 6 (Figure 4). In order that it may be adjusted to take up wear between the parts, it is shown as carried at one end on a tapered portion 2 of the shaft 6, its inner surface being correspondingly-tapered and at its other end it is carried on a conical sleeve 2I2 which may be provided with suitable means for adjusting it axially in order to take up wear and to properly center the sleeve 2I0. It is also angularly adjustable to present different surfaces for engagement by controlled parts as will later appear.

Each of the wheel units carries a shoe 2I5 which bears against the outer face of this sleeve 2I0and as the wheel units are reciprocated as just described to effect traverse motions between the wheel and the work, these shoes slide in contact with the sleeve 2I0 lengthwise. The uppermost wheel unit, as shown in Figure 14, is so disposed that its weight holds its shoe 2| 5 into contact with the outer face of the sleeve 2I0, but the lower wheel units as shown are 50 disposed that they must be held up against this sleeve, as by one or more springs 2I6. Aside from these springs, the two lower units differ from each other only in reversal of certain parts with relaa piston rod 242.

tion to each other. The right hand lower un t and the upper unit are identical.

The general arrangement of the parts is best shown in Figures 18 to 22. Referring first to Figure 18, it will be noted that each of the shoes 2!5 is carried within a slot 226 in an arm 22!. It is mounted with capability of rocking within this slot, being supported on an eccentric portion 222 of a pivot pin 223 threaded at its inner end as at 224 in a socket within the arm 22!. Its opposite end is provided with a slot 225 by, which the pin may be turned to adjust the amount by which the shoe projects from the outer face of the arm 22!. The outer face of the shoe is shown as convex laterally and straight longitudinally to bear over an extended length along the surface of the sleeve 2H1. The arm 22! is shown as pivoted at one end at 221 on a bar 228. This bar 228 is axially adjustable for a purpose which will later appear, but in so far as the normal wheel feed is concerned, the pivot 221 may be regarded as the fulcrum of the arm 22! carried in a bracket 23!! secured in any suitable manner to the housing I51. Near the opposite end of the arm 22! it has set thereinto a hardened wear piece 235 which is formed as the head of a plug 236 removably seated in a hole 231 through the arm 22!. Against this wear piece engages the outer face of an eccentric 238 formed on a rock shaft 239 (see Figure 19). This rock shaft has keyed thereto a pinion 240 which meshes with a rack bar 24! on This piston rod has secured thereto a piston 243 riding within a fluid pressure cylinder 244. The piston 243 is normally held at its inner limit of motion as by a spring 245 surrounding the rod 242 and reacting between a collar 246 secured thereto and a sealing member 241 which acts as a packing for the rod 242 adjacent to the piston 243. By introducing fluid pressure back of the piston 243, as through the port 248, the piston may be driven to the right as viewed in Figure 18 thus moving the rack bar 24! and rotating the eccentric 238 which acts to rock the arm 22! outwardly. This acts to move the wheel head away from the axis of the shaft 6 and produces a feed of the grinding wheel into the work. This feed, it will be noted, is substantially radial to the axis of the shaft 6 and thus substantially perpendicular to the direction of indexing motion of the work head as previously described, so that any inaccuracy in exact setting of the work head will have minimum effect in relation to the feed of the wheel relative to the work.

Provision is also made for effecting a feed of the wheel to provide for the decrease in size of the wheel due to wear and truing and this additional feed is efiected by moving the fulcrum 221 of thearm 22!. Thus the arm 22! is in effect fio-atingly supported, being movable both at its free end and at its fulcrum end and controlledby different mechanisms. The means -for producing the feed to compensate for wheel wear and truing is effective on the bar 228. This bar is provided with a threaded portion at 250 with which engages an internally threaded portion of a sleeve 25!. Keyed to this sleeve 25! is a worm wheel 252 which is held against axial motion so that through its rotation the bar 228 is moved axially. Meshing with the worm wheel 252, as shown best in Figure 21, is a worm 255 having a shaft 256. This shaft at one end has fixed thereto a gear 251 having relatively fine teeth which may be ratcheted around in. order to rotate the shaft 256 and adjust the bar 228 axially. The shaft 256 is journaled in a pair of alined bushings 268 and 26! which extend beyond their supporting frame at both ends and on these extended ends are joumaled the opposite arms 262 and 263 of a yoke 264. On one end of this yoke 264 is secured an arcuate arm 265 and to this armis pivoted, as at. 266, an arm 261 which carries at its outer end a spring ratchet 268. By rocking the arm 261 about its own axis 266 toward the axis of the gear 251 and also at the same time swinging the yoke 264, the spring pawl 266, engaging between the teeth of the gear 251, causes this gear to be rotated step by step in the direction of the arrow shown in Figure 20. This rocking of the arm 261 to bring the pawl into engagement between the teeth of the gear and also to rock the yoke 264 is produced by mechanism including a link 21!! having ball ends, one end of which engages in a socket 21! in the arm 261, and the other end in a socket 212 in one end of an arm 213 shown best in Figure 21. This arm 213, as shown best in Figure 22 is secured to a rock shaft 214, and it is not only urged outwardly to lift the ratchet 268 out of contact with the gear 251 but also to hold the portion 264 against an adjustable stop screw 215, by a torsion coil spring 216. This spring surrounds a bearing boss 211'and at one end hooks over a pin 218 on the arm 213 and its other end is secured as by the screw 219 to the boss 211. This shaft 214 extends through the bracket 238 and at its opposite end has secured thereto a finger 280 (see particularly Figures 4, 22 and 23). It should be understood that there is one of these arms 26!! for each of the grinding wheel units and each lies in the path of motion of an actuating lug 28! carried by a circular portion 262 of a spider 283. This spider 283 passes along between two'of the grinding wheel units, as shown best in Figures 4 and 14, and terminates at its other end in a portion 284 rockably mounted on the inner end portion of the sleeve 2H1. As will later appear, this portion 284 carries the truing diamonds for the several tools and is rocked to bring these tools into and out of truing relation to the grinding wheels and to bring the lugs 28! into proper angular position to coact with the arms 280. During the last 15 of indexing motion, the lugs 28!, which are then opposite to the arms 280, are rocked into contact with and rock these arms to effect a ratcheting of the compensating feed mechanism as previously described, this being done by rocking the shaft 214 to bring the arm 213 inwardly, engaging the ratchet 268, and turning the arm 264 away from the stop 215. By adjusting the initial position of the stop 215, the amount of this ratcheting can be adjusted as described, and when so adjusted the position of the stop 215 may be fixed by tightening a screw 285 engaging the split portion 286 of the bracket 281 through which the stop screw 215 is threaded. The member 284 is provided with an outwardly extended annular flange 290 which houses one end portion of an accordion pleated guard member or boot 29! which engages at its other end against a plate 292 secured to the inner face of the housing !58, preferably engaging beneath an annular retainer 293 thereon, as shown best in Figure 5. This acts to shield the bearing parts to the right of.the plate 292 from access by foreign particles from the grinding operation. Acting in conjunction with this member 29! are other guard elements about each wheel unit as shown at 295. The guard 29! insures sealing of the parts throughout the range of relative axial motions of the work-holding of this machine that-the positions of the wheels are accurately used by the outer face of the sleeve 213 with which the shoes 2" engage and in order to insure high accuracy the sleeve 2|. may be adiusted angularly from time to time to bring fresh surface portions intooperative engagement with the shoesjll.

Wheel mm mechanism The truing mechanism is carried by the rocking spider 233 hereinbefore mentioned in connection with the compensating wheel feed mechanism. Adjacent to each of the wheel units this spider 233 is extended, as at 333 (see Figure and each of these extensions is provided with an opening 3" therethrough. One portion of this opening "I is substantially circular in outline, but it is provided with a lateral extension 392 which is of a width less than the full diameter 'of the circular portion. Extending into this extension 332 of the opening are the truing devices or diamonds at 333, and on rocking of the spider 233 these diamonds may be brought from the full line inoperative position, shown in Figure 15 to the dotted line position in operative alinement with the grinding wheels so that as the shaft 6 is moved toward operative grinding position, the truing devices are brought across and true the grinding faces of the wheels.

Thespider is normally held in its inoperative angular position, as by a spring 333 which engages at oneend a hook 333 secured to a portion of the wider 233 and is fixed to a fixed part of the frame at the other end. This hook 333 is shown as secured to one arm of a forked portion 331' of the spider, this forked portion being formed by a slot 333 extending inwardly from one edge and within which is rockably mounted a tripping finger 339. As shown in Figure 17, one end of this tripping finger extends through an opening 3|. in the spider in position to be contacted at certain times by the head 3 of a stud 3l2 secured to a portion of the housing 9 within which the work-holding heads are pivotally mounted. This finger 339 is normally held in the position of Figure 1'! with its end projecting through the opening 3", as by a leaf spring 3". When in this position, as shown in Figure 17, the lug 3H contacting with the side face of the finger-339, causes the rockable housing 234 to .be turned about the axis of the shaft 3 with the housing 9 as the work holders are indexed throughout the final fifteen degrees of the index-- ing motion. This rocks the spider 233 to the dotted line position shown in Figure 15 where the diamond truing devices are in operative relation to the grinding wheels. As the shaft 3, with the parts' carried thereby, is moved axially toward operative. relation to the grinding wheels, and'has passed the wheels so that truing has been effected, the end 3!! of the arm 309 impinges upon a stud 3|! secured to the plate 292 so that further axial motion of the shaft 3 rocks the finger 309 into the position shown in Figure 16, releasing the finger 309 from the stud 3| I, and permitting the spider 233 to be rocked back to its inoperative position, as shown in full lines in Figure 15, where the diamonds are out of axial alinement with the surface to be true-d.

n will be noted as each or, the diamonds is independently adjustable in its mounting in the spider 333 so that thewheels can be true'd to sizes independent of each other, thus to provide for successive grinding operations in the three stations where grinding wheels are positioned to determine, independently, the amount of ,stock to be removed by each wheel. It will be"noted that the-outer wall of the opening 302 is formed by a spring arm 323 integral with the spider 233 at one end. The free end of this spring arrn may be clamped to an oppositely disposed portion 32I as by a clamping bolt 323, a felt piece being placed between the parts at 324 to keep out dirt and dust while permitting adjustment. This provides an additional means of close final adiustment of the truing diamonds 333.

Work spindle loading and unloading mechanism from this station and supplying thereto a new piece to be ground, between the indexing actions of the machine. This work loading and unloading mechanism is shown more specifically in Figures 40 to 46. A bracket 350 is secured to the top portion. of the casing part I50 and carries a hydraulic cylinder 35l. Within this cylinder is reciprocable a double acting piston 352, an intermediate portion of which is provided with rack teeth as at 353 which mesh with a-gear 354. This gear 354 is mounted on a rock shaft 355 which is provided at one end with an arm 353. Pivoted to the outer end of this arm, as at 351,

is one end of a link 353, the other end of which is pivotally secured as at 359 to a rack bar 330.

-This rack bar is slidable in a guide bracket 3' spring fingers 369 having their ends bent to form projecting work-retaining ribs 310. These spring fingers may be thrust into the opening in the work piece W and will spring outwardly to hold the work piece thereon, the fingers being so shaped that they can be engaged either in ground work or work to be ground, so that they may be employed not only to remove the finished work from the spindle at the loading position, but also to engage work to be ground and inserted into proper position in the work-holding mechanism of the spindle. A shoulder portion 315 on the block 366 limits the extent to which the fingers 369 may be projected through. the work. The work pieces to be ground are supported in a chute 313 (see Figures 40 and 42) which is partly closed off on one face by marginal strips 311 and 313'so that the work pieces are kept in a single line. The lower end of the chute is turned downwardly and inwardly, as shown at 319, and terminates with a rounded shoulder 383 which prevents the workpieces spring 385. This spring reacts between a portion 388 of the chute and an adjusting plug 381 threaded through the end portion 384.

Means are provided by which when one work piece is removed from the lower end of the chute the next is prevented from feeding down until the loading arm is properly positioned to receive it. This mechanism comprises a pair of stop pins 398 and 391, which are so spaced, as shown in Figure 42, as to permit but a single work piece to lie therebetween. These pins 398 and 391 have headed outer extremities, as 392 and 393, provided with cross pins 384 and 395 (Figure 43). These pins are engaged in slots 396 and 391 in opposite ends of a lever 398 fulcrumed at 399 to a fixed part 466 extending from the rear face of the chute 316. This lever 398 is provided with an extension arm 491 which is in position to be engaged back of the onset portion 368 of the loading arm 364, so that as the loading arm is swung up from the full line position, as shown in Figure 40, to the uppermost dotted line position, it contacts with the extension 4M and rocks the lever 398 to force inwardly the pin 390 against the action of a spring 402 to interpose a stop between the two pieces of work at the bend in, the lower end of the raceway and to withdraw the stop pin 39l so as to permit the work piece shown between the pins 398 and 391 in Figure 42 to drop below the pin 39! into loading position, as shown in Figure 40. Consequently swinging of the loading arm 364 in clockwise direction from the upper dotted line position causes its spring fingers 310 to engage this piece of work, and further swinging of the loading arm 364 in the same direction causes this work piece to be moved out of the raceway past the spring finger ends 382 and finally delivers it into the full line position in Figure 40 between the clamping jaws 35 of the work-holding mechanism of that spindle which is in loading position at that time. The jaws are then closed upon the work by the motion of the clamping plunger 31. The loading arm 364 is swung back to the lower dotted line inoperative position, by continued counterclockwise rotation of the gear 354 moving the arm 356 beyond its dead center position and causing reversal of the motion of the rack bar 360 and consequent with drawal of the loading arm, and there remains until after the next indexing of the work holders which brings a finished piece of workinto the unloading and loading station. The arm 364 is then again moved into the full line position shown in Figure 40 to engage the finished piece of work, after which the jaws 35 release the work and it is carried back by a swing of the loading arm 364 in counterclockwise direction to the upper dotted line position shown in this figure, all by rotation in clockwise direction of the arm 358 which first moves to dead center position and then away therefrom, imparting first clockwise and then counterclockwise motion to the arm 364. As the work" piece passes back into the chute 316, the back face of the work piece impinges upon the front faces of the hooked extremities 382 of the fingers 38i which cannot yield in that direction to permit it to pass. Consequently further retraction of the loading arm 364 causes the spring fingers 310 to be pulled out from the work, thus releasing it so that it may drop into the lower chute 485 (Figures 42 and 43) from which it may be conducted to any suitable point. This movement of the loading arm 364 to release the finished work has caused the rocking of the lever 398 so that an umground piece is released by the pin 39l to descend into position to be taken on the next clockwise swing of the loading arm 364. The motions of this loading and unloading arm are controlled by reciprocation of the piston 352 under the control of valve mechanism which will later be described.

Hydraulic drive and controt mechanism The operations of the various mechanisms are controlled through hydraulic valves which are actuated in timed relation to each other to perform the desired cycle of operations by power. This power is derived from the motor 450 having a drive pulley 45l on its armature shaft. A belt passing about the pulley 45l also passes around a driven pulley 452 (see particularly Figure 11) which is journaled on a shaft 453, as shown, through suitable roller bearings at 454. To the hub 455 of this pulley is secured a ring 456 having a clutch face at 451. This ring 456 may be secured as by a series of screws 458 which pass through the hub 455 and are threaded into a retaining ring 459 on the other face of the hub. Cooperating with the clutch face 451 is a mating clutch face 460 on a ring 46I which is pinned to a collar 462 keyed to the shaft 453. A nut 465 threaded on the end of the shaft 453 holds the parts in position. The pulley 452 is permitted axial as well as rotary motion relative to the shaft 453 so that its clutch face 451 may be brought into or out of clutching relation to the clutch face 469 of the ring 46l. Thus the pulley 452 may be clutched to or released from the shaft 453. This motion of the pulley 452 is controlled by a shifter yoke 410 which engages on opposite faces of the pulley and is secured to an axially movable bar 4" to the opposite end of which is secured a piston 412 riding in a hydraulic cylinder 413. The end of the bar 411 is extended through the piston 412 and is adapted to impinge on an adjustable stop screw 414 threaded through the end cap 415 of the cylinder 413 thus to limit the axial motion of the bar 411 in one direction. Thus it will be seen that hydraulic means is provided for clutching and unclutching the driven pulley 452 to its shaft 453. A cam shaft 480 is drivenfby the shaft 453 at a slow rate through reduction gearing. This gearing comprises a planetary reduction mechanism driven directly from the shaft 453 and another chain of gearing which will later be described.

The planetary gearing comprises an eccentric enlarged portion 48! of the shaft 453 to which is pinned opposite arms of a U shaped yoke 482 so that as the shaft 453 is revolved, this yoke is revolved with it. Between the sides of the yoke there is rotatably mounted on the shaft 481 an external gear 483, this gear being given a bodily rotation about the axis of the main portion of the shaft 453 as this shaft is rotated the yoke 482 counterbalancing this gear. It 

